Automatic air shutter for oil burners



P 1941- H. B. DONLEY ET AL AUTOMATIC AIR SHUTTER FOR OIL BURNERS Filed May 9, 1958 2 Sheets-Sheet 1 ep 16, 1941. H.BV.DONLEY mt 2.255.911

AUTOMATIC AIR SHUTTER FOR OIL BURNERS Filed ays, 195a g 2 Sheets-Sheet 2. T

I'II/IIIIIIIA Qua/mm Patented Sept. 16, 1941 AUTOMATIC AIR SHUTTER FOR OIL BURNERS Harold B. Donley and Samuel Johnson, Columbus, hlo,- assignors to Columbus Metal Products Inc., Columbus, Ohio, a corporation of Ohio Application May 9,

8 Claims.

invention has particular reference to oil burning apparatus utilizing a hydroxylating combustion vessel in association with thermostatically governed means for delivering oil at various rates 01' flow to the burner vessel to provide for low, intermediate and high stages of combustion, together with cooperative means for delivering air to the vessel at differing flow rates in accordance with said stages in order to effect carburetion and combustion of the oil supplied to the vessel.

In automatically controlled oil burning apparatus of this character, considerable difficulty has beenencountered in the matter of securing reliable and efficient means for obtaining the proper volume of air delivery under forced flow, conditlons to the oil vaporizing and combustion vessel in such quantities as to secure proper burning of the oil during the diflerent stages of combustion. In the hydroxylating type of burner, to which the present invention is particularly applicable, critical relationships obtain in the relative proportions of the oil and air supplied to the vessel. That is, if the ainount of air supplied to the vessel for a given rate of combustion is deficient, smoke and carbon producing combustion takes place with inefli'cient combustion and if an excess quantity of air is supplied, there is a tendency to curtail combustion and to interfere with flame propagation.

It is, therefore, an object of the present invention to provide novel means for supplying the burner vessel with correctly proportioned 1038, Serial No. 206,800

quantities of oil and forced air through the several combustion stages of the burner so that effi-' cient combustion of the hydro'xylated fuel mixture will be obtained in accordance with each of T said stages.

Another object of the invention resides in the provision of a motor driven fan or blower for delivering air under forced flow to the burner vessel and to provide the casing of the fan or blower 'with an air inlet equipped with a movable shutter device adapted to vary the effective area or the inlet in a manner automatically proportioned to the flow of oil to the burner vessel.

A further object of the invention rests in a motor driven fan or blower for oil burning apparatus wherein the adjustable shutter for controlling the efiectivearea of the air inlet for said and wherein electrically heated thermostatic means is provided for effecting the opening and closing of the shutter by swinging movement thereof about itspivotal mounting.

For a further understanding of the invention, reference is to be had to the following description and the accompanying drawings, wherein:

Fig. 1 is a view partly in vertical section and side elevation of oil burning apparatus embodying the features of the present invention;

Fig. 2 is a side elevation of the air inlet side of the casing of the fan or blower used in connection with the oil burning apparatus and disclosing the automatically controlled shutter mechanism for varying the effective area of the air inlet;

Fig. 3 is a vertical sectional view taken through the fan or blower casing, disclosing the air inlet, the pivoted shutter device and the thermostatic means for automatically controlling the operation of said shutter device;

Fig. 4 is a horizontal sectional view on the line IVIV of Fig. 3; l a

Fig. 5 is a detail vertical sectional view on an enlarged scale of the electrically heated thermostatic element employed for controlling the operation of the air inlet shutter;

Fig. 6 is a view in side elevation, with parts being broken away and shown in section, of the thermostatically operated metering valve, and its associated elements, used for varying the rate of oil flow to the burner vessel of the apparatus;

Fig. 7 is a horizontal sectional view on the plane indicated by the line VII-VII bf Fig. 6, disclosing the electrically heated thermostat elements for controlling the operation of the metering valve;

.Fig. 8 is a detail vertical sectional view on the plane indicated by the line VIII-VIII 01' Fig. 7 and disclosing the yoke members and associated movement limiting stops for governing the operation of the metering valve;

Fig. 9 is a similar view taken on the plane disclosed by the line IX-DI of Fig. 7 and illustrating one of the electrically heated thermostats for fan or'blower is pivotally mounted on the casing trical terminals and associated conductors used known hydroxylating type.

. utilized by the apparatus.

In the drawings, the numeral I designates the "1011 burning apparatus in its entirety. Essentially, this apparatus comprises a burner vessel 2, a motor driven fan or blower 8, an air conducting conduit 4 between the-outlet of the fan or'blower and the air inlet of the burner vessel 2, a metering valve 5 for governing the flow of oil at different rates to the bottom of the burner vessel 2, and associated automatic control devices for use in connection with the fan or blower and the valve 5, as will be hereinafter described.

In the practical embodiment of the invention illustrated, the vessel 2 is formed from sheet metal and includes a concave bottom wall 6 which terminates in an upstanding peripheral flange 'I, the latter cooperating with an annular side wall 8 in which is formed rows of spaced airadmitting apertures 8 of restricted size. A frusto-conical baiiie I is positioned on supporting pins extending inwardly from the wall 8 and divides the interior of the vessel into upper and lower chambers II and I2 respectively. The burner vessel is arranged concentrically within an outer casing I3 and a cylindrical partition wall [4 is arranged between the walls of the casing l3 and the side wall 8 of the vessel 2, the lower edge of the wall 14 being spaced from the closed bottom wall ii of the casing l3. s

The discharge end of the conduit 4 is connected with the edges of an opening produced in the casing I3. A frame I6 is arranged below the 'casing lit to effect the support of the latter withsource of oil supply, passes through the conduit 4 andenters the lower portion of the vessel 2 in order to produce a pool of liquid oil of variable area on the concave bottom 6 of said vessel.

The burner vessel described is of the well- Air constantly supplied under the forced draft of the fan or blower 8, passes through the conduit 4 and is deflected by the-partition wall I4 so that it circulates around the burner vessel, passing downwardly between the lower edge of the partition wall 14 and the bottom wall l5 of the casing l8. The air then flows in an upward direction; sweeping across the bottom 6 of the burner vessel 2 and flowing upwardly into the annular space formed between the side wall 8 of the burner vessel and the partition wall H. The air enters the interior of the burner vessel in accurately metered quantities through the small ports or apertures 8 provided in the side wall 8. The air thus entering the burner vessel is mixed with the oil vapors arising from the pool of oil maintained in the bottom of the vessel, producing a carbureted or hydroxylated mixture which is burned either within the confines of the vessel or exteriorly thereof. Through the operation of the metering valve 5, oil is delivered to the bottom of the vessel 2, and in the'present embodiment of the invention, at three different rates of flow.

During low stage operation, when the minimum amount of oil is supplied to said vessel, vaporized oil is admixed with sufllcient air so that active flame-producing combustion takes place within the upper chamber II of said vessel immediately over the baiile I8.

Under this condition of operation, the primary air for producing vaporization or hydroxylation enters the vessel through the apertures formed in the side wall 8 below the baffle l0, and secondary air for completing combustion enters thevessel through the apertures of the side wall above the baflie It.

When the supply of the oil to the burner vessel through the operation of the metering valve has been sufficiently increased to produce an intermediate stage of combustion, a portion of the active flame producing combustion actually occurs in the upper portions of the chamber II and above the burner vessel, so that the rows of apertures 9 above the baflle l0 may be used for supplying both primary and secondary air.

When the burner apparatus is operating on high-stage combustion conditions, with a maximum supply of oil being delivered to the bottom of the burner vessel, the apertures 9 serve to admit primary air into said vessel for the carburetion or hydroxylation of the oil and oil vapors so that the observable flame during this stage of operation is disposed above the deflector ring IS, the flame possessing a bush-like outline.

The successful operation of a burner of this character depends upon the properly proportioned flow of air and oil for each combustion stage to the vessel 2. These proportions are quite sensitive and if disturbed materially, undesired combustion of fuel mixture results. It is also a practical necessity to provide these different combustion rates through the use of automatic controls, since manual operation and adjustment are not feasible. It is to the attention of such automatic control and proportioned blending of the air and oil supplies that the present invention is particularly addressed.

At the outer end of the conduit 4, there is disposed a base 2|, surmounted by a removable casing 22. Arranged on the base, within the conflnes of the casing 22, is a supplemental oil receptacle 23. Oil obtained from a supply tank, or other source of supply, enters a chamber 24 formed in the receptacle 23 and a constant level of the 011 thus delivered to the chamber '24 is maintained in the chamber by the operation of a float valve mechanism, not shown. A sumcient head of oil is maintained within the cham ber 24 to provide for its gravitational flow through the pipe 20 to the bottom of the vessel 2. In the event of non-combustion of the oil within said vessel, the float valve mechanism operates as a safety measure to arrest further inflow of oil from the source into the chamber 24after a predetermined level of oil has been reached in the bottom of the burner vessel.

The pipe 20 enters the bottom of the receptacle 23 as indicated at 25 in Fig. 6, and the metering valve 5 regulates the rate of oil flow from the chamber 24 into the pipe 20 in accordance with fuel demands. The metering valve 5 comprises a cylindrical body slidably mounted for vertical burner vessel, only the restricted upper end or ends of the slits 26 are arranged above the bottom of the receptacle 23 to permit or the flow of oil from said float chamber into the oil supply line 20. When a larger amount of oil is required to provide for an intermediate stage of combustion,

wherein a larger amount of heat is developed, the present invention includes automatic means for raising the valve a limited distance so that a still greater area of the slit or slits 26 will be disposed above the bottom of the receptacle 23 to admit of a greater outflow of oil from the chamber 24 into the oil line 20. When a high stage rate of combustion is desired, further elevation of the valve 5 is secured so that the wider lower portions of the slit or slits 26 will be. exposed to the interior of the float chamber 24, thereby producing a maximum flow of oil to the burner vessel. p

While but one intermediate stage of operation has been described, it is, of course, within the range of the invention to employ one or more of such intermediate stages.

These several positions of the oil metering valve are automatically obtained in the present instance by the inclusion of electrically heated thermostats, indicated at 21 and 28 in Figs. 6 and 10. These thermostats each comprise substantially circular bimetallic strips, wherein one end of each strip is stationarily mounted on a convenient support, while the other or free end is able to flex or move in response to temperature variations. Within each thermostat, there is arranged a resistor coil 29, which is adapted to be heated by the passage of electric current therethrough in order to produce the requisite temperaturevariations to effect the required expansion and contraction movements of the thermostats. To control the passage of current through the coils 29 of said thermostats, reference is to be had to the diagrammatic view, Fig. 13, of the drawings. In this figure, the leads 30 of a commercial 110 volt house circuit are connected with conductors 3| which lead to the primary side of a voltage reducing transformer 32. Also connected with the conductors 3| is a shunt circuit 33, in which is positioned the electric motor '34, employed for eifecting the operation of the fan or blower 3. A

From the secondary terminal of the transformer, a conductor 36 extends through a voltage limiting switch 31 and a conductor 38 to one terminal of a room thermostat 39. It will be understood, of course, that the thermostat 39 may be placed in any location where regulated heating is desired. The free end of the thermostat 39 is disposed for consecutive engagement with the.

- ary side of the transformer 32..

The'heating of the coil 29 causes fiexure of the thermostat 21 so that the free end thereof, by being positioned in a recess 46 (Fig. 9) causes the oscillation of a yoke 41 which is freely supported for pivotal movement on a stationary rod 43. The yoke 41 includes an arm 49, which is to elevate the metering valve to its intermediate position. The stoppage of the valve in this intermediate position is secured by providing the outer end of the arm 49 with an offset portion 5| which is arranged in the plane of the lower end of an adjustable stop inthe form of a set screw 52.

If the demand for heat should be greater than that which intermediate stage combustion will supply, the free end of the room thermostat 39 engages with the contact 40. Current then flows from the thermostat 39 through a conductor 53, which leads to a resistor 54 provided in a fan shutter thermostat 55, to be hereinafter more particularly described. From the resistor 54, current passes by way of a conductor 56-to a resistor coil 29a arranged in the thermostat 28, and after passage through the coil 29, current is returned to the secondary terminal 45 by way of the conductor 44.

The heating of the coil 29a flexes the thermo- Stat 28 so that the lip 51 formed at its free end engages the lower reduced end 58 of a second yoke 59 pivotally mounted on the rod 48. This yoke is formed with an arm 60 which extends parallel with the arm 49 of the yoke 41, but is somewhat shorter in length, the free end of the arm 60 being disposed in the annular groove 50 in the upper end of the valve 5, but on the op posite side of the latter as regards the arm 49- (Fig. 7). Due to the'position of the arm 69, the upward movement thereof is not influenced b1 the set screw 52, so that greater movement may be imparted to the valve 5 by the arm 66 than can be imparted to said valve by the arm 49, thus enabling the metering valve to be elevated to its maximum extent when under the influence of the operation of the thermostat 28. When the arm 66 contacts with an adjustable stop in the form of a set screw 6|, the metering valve will have been elevated to its maximum point in order to provide for the maximum outflow of oil from the float chamber 24 to the vaporizing burner.

By means of these themostat devices, accurate metering of the oil flow to the burner -vessel is obtainable for establishing the diflerent stages of combustion. As previously pointed out, it is also important, particularly with the use of a hydroxylating burner, to vary the amount of volume of air delivered to the burner vessel in proportion to the oil supplied thereto. This is secured by the apparatus disclosed in Figs. 2 to 5 of the drawings. In these figures, the casing 62of the fan or blower has-one of its verticalside-walls provided with an air inlet opening 63 of fixed area. Normally covering this opening is a pivotally movable shutter device 64 whichis so mounted that it may swing outwardly from the side wall of the casing 62 to uncover the opening 63 so as to provide for free airflow into the interior of the fan or blower/ in response to the operation of the impeller 65 of the latter. In this embodiment of the invention, the shutter device 64 is provided at one sideewith a constantly open port 66 of relatively small diameter which, evenwhen the shutter is in closed position, admits of limited air in flow into the fan or blower. If this limited inflow of air should be insufllcient, the shutter device 64 includes a somewhat larger axially disposed port 81, which may be opened or closed by a pivoted disk 68, the latter retaining its adjusted positions through frictional contact with the outer surface of the shutter 64,

We have found, as a practical matter, that through the use of the ports 66 and 51, a sumcient amount of air will be admitted into the fan or blower to produce efficient combustion of the oil during both low and intermediate stages of burner operation. However, for high stage operation, it is essential that the air inlet 53 be fully opened, and in view of the nature of the apparatus, it is also necessary that such opening should take place automatically, together with the closure of the inlet following the termination of the high stage period of combustion.

This can be simply accomplished by providing the shutter device 54 with a flange 69. Passing through this flange is the shank of a headed bolt 10, which projects upwardly into asmall casing I l,..connected with the side of the blower or fan. The upper threaded end of the bolt is equipped with an adjusting nut 12. As shown more par-- ticularly in Fig. 5, the lip 13 of the thermostat 55 is provided with an opening 14 for the reception of the shank of the bolt 10 so that the lip will engage with the rounded lower surface of the nut or washer I2.

Since the resistor 5| of the thermostat 55 is wired in series with the resistor 29a of the thermostat 28, it follows that both of these resistors;

will be simultaneously energized. This results, as previously explained, in the full opening of the metering valve 5, and in suflicient flexure on the part of the thermostat 55 to cause the eleva- ,tion of the bolt HI to such extent as to swing the shutter device 64 about its pivotal mounting and cause the required full opening of the air inlet 63. When the high stage period of operation is terminatedby the operation of the room thermostat 39; the resistor 54 cools and the strips 55 returns to its normal position, thus lowering the shutter'device and again closing the fan inlet 63 to the position shown in Fig. 3.

It is believed, in view of the foregoing descriphydroxylating oil burners to operate efficiently with minimum soot and carbon formation through several stages of combustion, enabling clean combustion to be produced at .each stage well adapted for the heat demands present.

-While the apparatus in-its preferred and commercial form has been set forth, it will be understood that the same-is subject to certain variation or modification without departing from the scope of the invention as the latter has been defined in the following claims.

What is claimed is:

1. In automatically controlled oil burning apparatus of the type having a burner vessel and a fuel line communicating therewith. valve means disposed in said fuel .line, said valve means being capable of movement between closed and open positions, motor driven means for supplying air to said burner vessel, electrically actuated thermo-responsive means for controlling the volume of air delivered to said'burner by said air supment of the valve means in responsethereto, and

thermostatic switch means having a pair of plying means, a pair of electrically actuated thermo-responsive members cooperating with said valve means to open the same to provide for fuel flow to said burner, stop means engaging the first thermo-responsive member of said pair to limit the degree of opening movement of the valve means in response thereto, and thermostatic switch means having a pair of spaced contacts, the first contact of said pair being connected with the first thermo-responsive valve actuating member, the second contact being connected with the second thermo-responsive valve actuating member and air controlling member whereby maximum air flow will be provided when the fuel valve means is fully opened.

2. In automatically controlled oil burning apparatus of the type having a burner vessel and a fuel line communicating therewith, valve means disposed in said fuel line, said valve means being capable of movement between closed and open positions, motor driven means for supplying air to said burner vessel, electrically actuated thermo-responsive means for controlling the volume of air delivered to said burner by said air supplying means, a pair of electrically actuated thermo-responsive members cooperating with said valve means to open the same to provide for fuel fiow to said burner, adjustable stop means I spaced contacts, the first contact of said pair being connected ,with the first thermo-responsive valve actuating member, the second contact being connected with the second thermo-responsive valve actuating member and air controlling member whereby maximum air flow will be provided when the fuel valve means is fully opened.

3. In oil burning apparatus of the type having a burner vessel, valve means for supplying liquid fuel to the burner vessel and motor operated means for supplying air to said vessel, control mechanism for said apparatus comprising electrically heated thermo-responsive members connected with said fuel valve means and air supply means to control the quantity of each supplied to said burner vessel, one of said thermos responsive members serving to actuate said fuel valve means to provide for partial flow of fuel, another serving to actuate said valve means to provide for full flow of fuel and a third thermoresponsive member providing fora maximum flow 01' air, thermostatic-switch means for controlling the flow of electric energy to said-thermoresponsive members, said switch means having a pair of stationary contacts and a movable contact, and circuit means connecting said switch means and thermo-responsive members with a current source, the first thermo-responsive member being connected with the first stationary contact of said switch, the other contact being connected with the second and third thermoresponsive members to provide for their operation in unison.

4. In oil burning apparatus of the type having a burner vessel, valve means for supplying liquid fuel to the burner vessel and motor operated means for supplying air to said vessel, control mechanism for said apparatus comprising thermo-responsive members for controlling the operation of the fuel valve means and the quantity of air delivered by said air supplying means, a pair of said members being associated with said fuel valve means, one of said pairproviding for a valve opening position,

partial opening of said valve means, a resistance coil disposed adjacent each thermo-responsive member, thermostatic switch means having movable contact means connected with a source of electric current, a pair of stationary contacts successively engaged by said movable contact means, the resistance coil adjacent said thermoresponsive member which partially opens the fuel valve being connected with the stationary switch contact first engaged by the movable contact, the other stationary contact being connected with the remaining resistance coils.

5. In automatically controlled oil burning apparatus of the (type having a burner vessel and means for conducting liquid fuel thereto, valve means for controlling the flow of fuel to said burner vessel comprising a casing, a valve mem ratus of the type having a burner vessel and means for conducting liquid fuel thereto, valve means for controlling the flow of fuel to said burner vessel comprising a casing, a valve member disposed in said casing for movement between open and closed positions, a pair of valve actuating lever elements engaging said valve member to impart opening movement thereto, means in said casing for limiting the degree of movement of one of said lever elements toward thermo-responsive means engaging said lever members, and electric resistance coils disposed adjacent said thermoresponsive means, the introduction of electric current to said resistance coils serving to heat said thermo-responsive means to cause movement of said lever elements and said valve.

a low stage, means for governing the quantity *of air delivered to said vessel, said means normally providing suflicient air flow to convert the normal fuel flow to a combustible mixture, thermo-responsive means connected with said valve to move the same to open positions to increase the flow of fuel to said vessel, additional thermo-responsive means connected with said air flow governing means, and thermostatic switch means connected in circuit with said thermoresponsive members, said switch means being op erable to effect the opening of said valve independently of and simultaneously with the opening of said air flow governing means.

8. In oil burning apparatus of the type having a combustion vessel, means for feeding liquid fuel to said vessel, continuously operated means for delivering air to said vessel, valve means for controlling the flow of fuel through said feeding means, said valve means normally permitting sufficient fuel flow to operate said apparatus at a low stage, means for governing the quantity of air delivered to said vessel, said means normally providing suflicient air flow to convert the normal fuel flow to a combustible mixture, thermo-responsive means connected with said valve to move the same to an open position to provide for suflicient fuel flow to sustain said apparatus at a high stage of operation, a second thermo-responsive device connected with said air flow governing means, and thermostatic switch means connected in circuit with said thermo-responsive members to cause simultaneous operation thereof.

HAROLD B. DONLEY.

SAMUEL JOHNSON.

D l s c L A 1 M E R 2,255,917.Hur0ld B. Donley and Samuel Johnson, Columbus, Ohio. AUTOMATIC AIR SHUTTER FOR OIL BURNERS. Patent dated September 16, 1941. DiseIaimer filed March 12, 1942, by the inventors; the assignee, Columbus Metal Products, Inc., consenting. Hereb enter this disclaimer to claims 5 and 6 of said Letters Patent.

' Gazette April 7, 1942.] 

